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Boundary Conditions Changing When Exported to Matlab

Posted Sep 25, 2012, 6:52 p.m. EDT Geometry, Mesh, Studies & Solvers, Structural Mechanics Version 4.3 0 Replies

J. Mendoza
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Hello Everyone,

I am using the 3D Structural Mechanics Beam Solver with a eigenfrequency study. In the comsol study I have it set to the standard free-free end conditions.
I use the codes below to extract the Mass (E) and Stiffness(K) matrices of the system with the live-link to matlab.
MA=mphmatrix(model,'sol1','out',{'K','D','E','L'});

K=MA.K;
D=MA.D;
E=MA.E;
L=MA.L;

I use matlab's eig to extract the eigen values and eigenvectors from the system. When I plot the mode shapes (extracted from the eigenvectors) the modes aren't consistent with free-free boundary conditions, they are consistent with sliding-sliding boundary conditions.

Is this a matlab problem or a comsol problem? Is there a way to fix it?

Thanks,

Joshua
0 Replies Last Post Sep 25, 2012, 6:52 p.m. EDT
COMSOL Moderator

Hello J. Mendoza

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